Adding contact shadows on glass table
The closest I was able to personally achieve that resembles your setup is below. It isn't perfect - it changes the look of the glass a little, and requires some very bright, or very close (or both) lights to be properly visible. As you can see from the image, I had to put the area light close enough that the light is glaring off the surface of the glass. It also seems that as is usual, the smaller the light radius, the better for the shadow. Therefore, keep the size of the area light as small as possible, and even consider swapping the sun for something else maybe even a very bright point light). However, one thing that works well in your favor is that the shadow shows up best at a shallow angle (like the one in your photo) so you can probably get away with less bright lighting. Also, the change in appearance of the glass shouldn't be as noticeable because the glass you are using is very thin. Regardless, have a try and see if it works, or at least gets you closer.